<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>圆角边框</title>
    <style>
        div {
            width: 500px;
            height: 200px;
            background-color: aquamarine;
            border-radius: 30px;
            padding: 0 30px;
        }
    </style>

</head>
<body>
    <div><img src="img/圆角边框实现.png" ></div>
</body>
</html>